Fence line openings in areas where cattle are raised are conventionally provided with ground level cattle guards which cattle are very reluctant to cross. This allows a gate opening to be maintained for the passage of vehicles therethrough without worry of cattle also passing through the gate opening. However, most cattle guards are quite limited in width and may be of sufficient width only to enable conventional vehicles such as automobiles, small trucks and narrow farm equipment to move thereover through an associated gate opening, but are not of sufficient width to allow heavy wide trucks and wide farm implements to pass through the adjacent fence opening. Further, although it would be possible to manufacture cattle guards of increased width to enable wide trucks and farm equipment to move through a cattle guard equipped opening, the provision of an overly wide cattle guard raises the possibility that more than a few cattle adjacent a wide cattle guard would move toward a wide fence opening if they were "spooked" with the result that at least several cattle on the approach side of such a cattle guard would be forced therethrough and perhaps receive severe foot or leg injuries.
Accordingly, a need exists for a cattle guard equipped fence opening which will allow wide loads to pass therethrough but which will have the appearance of a narrow cattle guard equipped fence opening at all times when a wide load is not passing therethrough.
In addition, various different forms of automatic closing gravity biased gates heretofore have been provided and such gravity biased gates could be utilized to fully close a wide cattle guard equipped fence opening. However, providing full width gravity biased closure gates for a wide cattle guard equipped fence opening would require that the gates be opened and closed each time a small vehicle is to pass through the gate opening and each such small vehicle to pass through the gate opening would have to at least substantially stop prior to engagement with the gravity biased gate or gates and then proceed slowly forwardly in order to open the gates. In addition, conventional small vehicles such as passenger cars and the pckup trucks do not always include front end portions which properly mate with gravity biased gates in order to open the same.
Accordingly, a need exists for a cattle guard equipped fence opening including the usual narrow cattle guard centered in a considerably wider fence opening and wherein the adjacent fence section ends are equipped with pivotally mounted wing gates or closure members gravity biased to the closed positions substantially closing the span between each side of the associated fence opening and the adjacent side of the cattle guard.
Examples of various different forms of gravity closed gate structures including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 272,619, 2,693,043, 2,925,674 and 3,222,806.